Showcase security system

ABSTRACT

The showcase is provided with a lock set that includes a key operated bolt which can be thrown only when the showcase door is closed. Accordingly, the key can be removed only when the case is locked. In counterpart, the authorized users are provided with keys secured on their persons, so no one can absent-mindedly or neglectfully walk off leaving the showcase unlocked.

United States Patent 1 1 1111 3,922,895

Greenebaum 1 Dec. 2, 1975 I5 SHOWCASE SECURITY SYSTEM 2.457J95 l2/l948 Bngnall. Jr. /457 v 3 l24,286 319(4 D (l 5 Inventor: Howard M. Greeneb'aum, Pasadena, Ompm 7 M 7 Primary E.\'aminerPaul R. Gilliam [73] Assignee: Chain-Lock C0., lnc., Ba e. Assistant E.\'aminerVict0r N. Sakran Md. Attorney, Agent, or Firm-Cushman, Darby & 22 Filed: Feb. 6, 1974 Cushma [2|] Appl. No.2 440,276 [57] ABSTRACT The showcase is provided with a lock set that includes [52] US. Cl 70/100, 70/457 a key Operated bolt which can be thrown only when [51] Int. Cl.-.q. F05B 65/00 the Showcasg door is closed Accordingly, the key can I58] held of em-ch 70/77 be removed only when the case is locked. ln counter- 70/90 part, the authorized users are provided with keys se- 292/DIG' 46 cured 0n their'persons, so no one can absent-mindedly 0r neglectfully' walk off leaving the showcase un- [56] References Cited locked.

UNITED STATES PATENTS v F l,59l.()l() 7/l926 Best 70/8l t Clams 2 Drawmg gums U.S. Patent Dec. 2, 1975 3,922,895

SHOWCASE SECURITY SYSTEM BACKGROUND OF THE INVENTION Jewelers, watch repairers, and other sellers of small valuable objects try to keep them under lock and key to prevent pilferage. Thus, display cases are often provided with locks and the authorized users, the store owners and certain employees are given keys thereto. However, it is easy to become so eng'rossed with trying to make a sale or in keeping track of others waiting to be served, that a case door opened to show an item inquired about is unintentionally left ajar or slid closed but left unlocked. When a discovery of the failure to relock the case is made, often nothing has been lost but the shopkeepers peace of mind. But the risk is there and sometimes thieves will take advantage of the situation.

SUMMARY OF THE INVENTION The showcase is provided with a lock set that includes a key operated bolt which can be thrown only when the showcase door is closed. Accordingly, the key can be removed only when the case is locked. In counterpart, the authorized users are provided with keys secured on their persons, so no one can absent-mindedly or neglectfully walk off leaving the showcase unlocked.

The principles of the invention will be further hereinafter discussed with reference to the drawing wherein a preferred embodiment is shown. The specifics illustrated in the drawing are intended to exemplify, rather than limit, aspects of the invention as defined in the claims.

BRIEF DESCRIPTION OF THE DRAWING In the Drawing FIG. 1 is a perspective view of part of a typical sliding door showcase with the lock of the invention in an open condition, showing the key inserted therein and secured about the authorized user; and

FIG. 2 is a perspective view of the case shown closed and locked.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT The showcase is provided with a sliding door 12. A lock housing 14 is secured on the door 12, e.g. with bolts 16. At a comparable position, for when the door 12 is slid fully closed, a catch 18 is provided on the case 10. According to the circumstances, the catch 18 may be a piece of hardware secured on the case, or a socket 20 cut in the case itself. The lock housing 14 is provided with a pin tumbler cylinder 22 which can be turned by a key 24 to thrust and retract a bar bolt 26. At all sites along the case rail 22 on which the catch 18 is provided, but for the site of the catch 18, the surface 28 is too close to the lock housing 14 to permit the bar bolt 26 to be thrust. Accordingly, the key 24 can only be turned to thrust the bar bolt when the door 12 is fully closed (in which condition the bar bolt 26 is aligned with the socket 20).

Within the housing 14 a lateral slot 30 slidably receives the bar bolt 26. The pin tumbler cylinder is keyed to the bar bolt 26'rack and gear fashion, so that as the key 24 rotates the pin tumbler mechanism, the bar bolt slides in the direction of the arrow 32. A stop 34 is provided at the opposite end of the slot 30 from the one from which the bar bolt is thrust when locking.

The stop is so positioned that when the bar bolt 26 is retracted, its opposite end 36A from that which does the locking hits the stop 34 at a point in the cycle of the rotation of the pin tumbler mechanism that leaves the key 24 at a non-withdrawable position. (Persons familiar with automobile ignition locks will recognize a similar construction used in such circumstances, which permits the key to be freely withdrawn when the ignition is of but, which otherwise prevents withdrawal of the key.)

It should further be noticed that the authorized user HG who bears the key 24 has it securely attached to his person near his waist by a chain 36 which is long enough to permit him to insert the key in the lock, but insufficient to permit him to leave the case unattended while the key is in the lock. A chain 36 measuring about eighteen inches from belt to key is typically appropriate.

Accordingly, the case can only be unlocked while a user is stationed in attendance thereto. It cannot be locked open, because the bar bolt would hit the surface 28 and the key cannot be withdrawn unless the case is locked. Thus a problem long a bane of jewelers and other shopkeepers is solved by use of the invention.

It should now be apparent that the showcase security system as described hereinabove possesses each of the attributes set forth in the specification under the heading Summary of the Invention hereinbefore. Because the showcase security system of the invention can be modified to some extent without departing from the principles of the invention as they have been outlined and explained in this specification, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.

In the claims:

1. For a showcase including a case portion having a door slides open and closed, a showcase security system, comprising:

a lock housing mounted on said door adjacent one side edge thereof;

a bar bolt slidably mounted on said housing for sliding toward and away from the case portion;

a key operable tumbler cylinder coupled to the bar bolt for thrusting and retracting the bar bolt toward and away from the case portion;

key means removably insertable into the tumbler cylinder for operating the tumbler cylinder;

the tumbler cylinder permitting removal of the key when the key is in a predetermined angular alignment with the lock housing corresponding to the bar bolt being in a thrust condition;

a bolt catch provided on the case portion, where it is in alignment with the bar bolt only when the door is slid fully shut;

boss means on said housing and positioned to be engaged by the bar bolt, upon retraction thereof, upon rotation of the key in a sense to retract the bar bolt, by less than an angular amount such as will again bring the key to said predetermined angular alignment, whereby the key is prevented from being withdrawn unless the door is closed and the showcase is locked.

2. The showcase security system of claim 1 further including a chain about 18 inches long having means at one end for attachment to an authorized user of the showcase and having said key mounted at the other end thereof. 

1. For a showcase including a case portion having a door slides open and closed, a showcase security system, comprising: a lock housing mounted on said door adjacent one side edge thereof; a bar bolt slidably mounted on said housing for sliding toward and away from the case portion; a key operable tumbler cylinder coupled to the bar bolt for thrusting and retracting the bar bolt toward and away from the case portion; key means removably insertable into the tumbler cylinder for operating the tumbler cylinder; the tumbler cylinder permitting removal of the key when the key is in a predetermined angular alignment with the lock housing corresponding to the bar bolt being in a thrust condition; a bolt catch provided on the case portion, where it is in alignment with the bar bolt only when the door is slid fully shut; boss means on said housing and positioned to be engaged by the bar bolt, upon retraction thereof, upon rotation of the key in a sense to retract the bar bolt, by less than an angular amount such as will again bring the key to said predetermined angular alignment, whereby the key is prevented from being withdrawn unless the door is closed and the showcase is locked.
 2. The showcase security system of claim 1 further including a chain about 18 inches long having means at one end for attachment to an authorized user of the showcase and having said key mounted at the other end thereof. 